1. Field of the Invention
The present invention relates to an imprint apparatus that molds resin dispensed on a shot region of a substrate and forms a pattern of resin on the shot region.
2. Description of the Related Art
Nanoimprinting is already known as an alternative to a method of forming a fine pattern on a semiconductor device using UV photolithography, X-ray lithography, or electron beam lithography. Nanoimprinting is a technique in which a mold on which a fine pattern is formed, for example, by electron beam exposure, is pressed against a substrate such as a wafer to which a resin material (resist) is applied, and thereby the pattern is transferred onto the resist.
There are some types of nanoimprinting. A light cure method is one of them (M. Colburn et al., “Step and Flash Imprint Lithography: A New Approach to High-Resolution Patterning,” Proceedings of the SPIE's 24th International Symposium on Microlithography: Emerging Lithographic Technologies III, Santa Clara, Calif., Vol. 3676, Part One, pp. 379-389, March 1999). The light cure method is a method in which an ultraviolet curing resin (resist) is exposed and cured with a transparent mold pressed against the resin, and then the mold is removed. Nanoimprinting by this light cure method is suitable for the manufacturing of semiconductor integrated circuits because temperature can be controlled with relative ease, and alignment marks on a substrate can be observed through the transparent mold.
Considering the superposition of different patterns, a step and repeat method is desirably applied in which a molds is tailored to the size of chips to be manufactured, and a pattern is sequentially transferred to shots on a substrate. In the case of pattern transfer by such a step and repeat method, if one transfer operation (to each shot) including pressing of a mold, exposing of light cure resin to light, and removal of the mold requires time, pattern transfer to the whole surface of a wafer (to all shots) also requires time, and this decreases the throughput of the pattern transfer apparatus.
To solve this problem, Japanese Patent Laid-Open No. 2008-006704 discloses a method in which throughput is enhanced by performing part of the operation of pressing or removing a mold in parallel with the step movement of a substrate. Japanese Patent Laid-Open No. 2007-266053 discloses a method in which a mold and a substrate are relatively moved in a direction parallel to the pattern surface of the mold to facilitate the spread of resin during the pressing of a mold, and thereby pressing time is reduced. Japanese Patent Laid-Open No. 2006-19464 discloses a method in which the removal of a mold is facilitated in a similar way.
Considering application to semiconductor devices, a pattern transfer apparatus using nanoimprinting is required to have not only a throughput enhanced by reducing resin spreading time during the pressing of a mold, but also a high superposition accuracy. The method disclosed in Japanese Patent Laid-Open No. 2007-266053, in which a mold and a substrate are relatively moved by a vibration generating mechanism, has a problem where the relative positions of the mold and the substrate are prone to be unfixed after the vibration generating mechanism is stopped. If alignment of the mold and the substrate is performed before the pressing of the mold, realignment is necessary.
The alignment after the pressing of the mold is not easy because a load is applied to the mold and the substrate. The time required for realignment reduces throughput. Although alignment is not mentioned in Japanese Patent Laid-Open No. 2006-19464, the method disclosed therein has the same problem because a substrate and a mold are relatively moved after the pressing of the mold.